Example Django + Zappa + pipenv

Example application using Django, Zappa, and pipenv.

Getting started

To get started update the Zappa configuration (zappa_settings.json) if you desire. Then deploy

zappa deploy dev

This example uses python-dotenv to configure your django application via environment variables. The last step is to configure the allowed host. Therefore, you need to find out the domain where your lambda function is hosted. This can be achieved by calling zappa status dev:

$ zappa status dev
zappa status dev
Status for example-dev:
        Lambda Versions:      2
        Lambda Name:          example-dev
        Lambda ARN:           arn:aws:lambda:eu-central-1:012345:function:example-dev
        Lambda Role ARN:      arn:aws:iam::012345:role/example-dev-ZappaLambdaExecutionRole
        Lambda Handler:       handler.lambda_handler
        Lambda Code Size:     22113064
        Lambda Version:       $LATEST
        Lambda Last Modified: 2020-05-08T13:08:25.738+0000
        Lambda Memory Size:   512
        Lambda Timeout:       30
        Lambda Runtime:       python3.7
        Lambda VPC ID:        None
        Invocations (24h):    0
        Errors (24h):         0
        Error Rate (24h):     Error calculating
        API Gateway URL:      https://xyz.execute-api.eu-central-1.amazonaws.com/dev
        Domain URL:           None Supplied
        Num. Event Rules:     1
        Event Rule Name:      example-dev-zappa-keep-warm-handler.keep_warm_callback
        Event Rule Schedule:  rate(4 minutes)
        Event Rule State:     Enabled
        Event Rule ARN:       arn:aws:events:eu-central-1:012345:rule/example-dev-zappa-keep-warm-handler.keep_warm_callback

Use the API Gateway URL domain and set it as an environment variable on the Lambda console for the variable ALLOWED_HOST. Furthermore, you need to set the bucket name where to serve your static files via AWS_STORAGE_BUCKET_NAME. For simplicity, you can use the one used by zappa.

And to make sure you have your static files served, call:

zappa manage dev "collectstatic --noinput"

Done!

How this project was created

Create a project folder

mkdir project-name
cd project-name

Create a virtual environment and install django and zappa (python-dotenv to manage environment variables):

pipenv install zappa django python-dotenv
pipenv shell

Then start a Django project

django-admin startproject example .

Important, note the . at the end to indicate to Django to create files within the directory.

Then create an app:

python manage.py startapp app

To maintain sanity over different settings, the original example/settings.py is organized in a settings package.

First, link the app in the config:

INSTALLED_APPS = [
    'app.apps.AppConfig',
    ...
]

As well as make sure that python-dotenv can get to work.

# example/settings/core.py

from dotenv import load_dotenv  # right after import os
from pathlib import Path

# replace BASE_DIR with
# if the original settings structure is kept remove one `.parent`.
BASE_DIR = Path(__file__).absolute().parent.parent

# And add a line to load environment variables
load_dotenv(BASE_DIR / '.env')

# Replace sensitive things subsequently with os.getenv
SECRET_KEY = os.getenv('SECRET_KEY', 'Default Secret (not)')
ALLOWED_HOSTS = [os.getenv('ALLOWED_HOST')]

Note that AWS does not support SQLite and you will need to replace the database backend with something workable:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.dummy',
    }
}

Once the basic settings are made one has to provide an adequate storage environemnt. This example is based on django-storages.

Create a configuration for Amazon S3 using again python-dotenv (see example/settings/storage.py).

Next steps

• Include how to connect to a database, e.g. Amazon Aurora.